The fish species of Hawaii inhabit the Hawaiian archipelago in the central North Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of Australia. The islands are part of the State of Hawaii, United States. The state encompasses nearly the entire volcanic Hawaiian Island chain, which comprises hundreds of islands spread over 1,500 miles (2,400 km). At the southeastern end of the archipelago, the eight "main islands" are (from the northwest to southeast) Ni'ihau, Kauai, Oahu, Molokai, L'nai, Kaho'olawe, Maui, and Hawaii. The Northwestern Hawaiian Islands include many atolls, and reefs. Due to Hawaii's isolation 30% of the fish are endemic (unique to the island chain).